5V/-12V/-15V or Adjustable, High-Efficiency, Low-I DC-DC Inverters

The MAX764/MAX765/MAX766 inverting switching regulators are highly efficient over a wide range of load currents, delivering up to 1.5W. A unique, current-limited, pulse-frequency-modulated (PFM) control scheme combines the benefits of traditional PFM converters with the benefits of pulse-width-modulated (PWM) converters. Like PWM converters, the MAX764/MAX765/MAX766 are highly efficient at heavy loads. Yet because they are PFM devices, they use less than 120µA of supply current (vs. 2mA to 10mA for a PWM device).

The input voltage range is 3V to 16V. The output voltage is preset at -5V (MAX764), -12V (MAX765), or -15V (MAX766); it can also be adjusted from -1V to -16V using two external resistors (Dual Mode™). The maximum operating VIN - VOUT differential is 20V.

These devices use miniature external components; their high switching frequencies (up to 300kHz) allow for less than 5mm diameter surface-mount magnetics. A standard 47µH inductor is ideal for most applications, so no magnetics design is necessary.

An internal power MOSFET makes the MAX764/MAX765/ MAX766 ideal for minimum component count, low- and medium-power applications. For increased output drive capability or higher output voltages, use the MAX774/MAX775/MAX776 or MAX1774, which drive an external power P-channel MOSFET for loads up to 5W.

Applications

* Battery-Powered Applications * LAN Adapters * LCD Bias Generators * Portable Instrumentation * Remote Data-Acquisition Systems

* High Efficiency for a Wide Range of Load Currents

* 250mA Output Current

* 120µA Max Supply Current

* 5µA Max Shutdown Current

* 3V to 16V Input Voltage Range

* -5V (MAX764), -12V (MAX765), -15V (MAX766), or Adjustable Output from -1V to -16V

* Current-Limited PFM Control Scheme

* 300kHz Switching Frequency

* Internal, P-Channel Power MOSFET